Process of dyeing cellulose acetates



Patented Aug 18, 1925.

UNITED STATES PATENT, OFFICE.

RENE GLAVEL, or nasal, SWITZERLAND.

rnocnss or nYnnie cnnn'onosn AonTnTns,

No Drawing.

To all whom it may concern."

Beit known that I, RENE CLAvnL, a citizen of the Swiss Republic, ofBasel, Switzerland, have invented a certain new and use-' ful ImprovedProcess of Dyeing Cellulose Acetates, of which the followingis aspecification. 1'

In the specification of a previous United States Patent No. 1,37 8,443,I have described a process accordin to which cellulose acetates inartificial silkiofilmor other form can be dyed with acid, dyestuffs, inpresence of relatively large quantities of one or more water-solublechlorides such as zinc chloride, stannous chloride, magnesium chloride,ammonium chloride, etc., and of acids, preferably or-] ganic, such asformic acid or acetic acid,

etc., one or more. protective colloids beingpreferably added, such forexample as elatine, gelatine soaps, albumen, boiled o liquor,tannates'or saponified or sulphonated fatty acids.

It has beenlproposed-in'U. S. patent specification 97 9,966 to produceazo dyes on cellulose acetate goods b development on the fibre ormaterial, an according to one example of the said specification theemployment' of sodium acetate was suggested to facilitate the absorptionof the base by the material.

It has now been found that advantages and improved results can beobtained in the dyeing of cellulose acetateswith the developing dyes orso-called ice colours by em ploymg in the base baths 0!: the developerbaths, or in both kinds ofbath a relative-- ly large quantity of aWater-soluble chloride or water-soluble chlorides such as referred to,together with protective colloid.,

The protective colloids such .as gelatin'e,

gelatine soaps, soaps, boiled-off liquor and so forth, are especially ofadvantage in cases wherethe bases or the developersare,

employed in the neutral or alkaline condition; 'As is known, many basesand developers cannot be employed/either neutral or alkaline, becauseprecipitation 'occurs.

asicor direct Application filed October 5, 1922. Serial No. 592,601;

By the employment of the protective colloids, precipitations orseparations are prevented and the bodies in question can be re liablymaintained in suspension. over, the protective colloids enable thebases, and developers to be taken up regularly b the fibre. 'Also it ispossible wlth the ai of the protective colloids to limit the alkalinityconsiderably in cases where alkalinity was ,necessary according to thecustomary process. I

The water-soluble chlorides-(which may be employed singly or more thanone together) ma consist by way" of example .of the chlori es ofmagnesium or calcium. Chloride of magnesium in particular may be usedwith advanta e by reason of its low molecular weight am? cheapness.

Example.

of sodium bicarbonate. The goods are washed once with soft water andonce with hard water and are then brought into a diazotizing bath of thesame volume of li uid as the first bath, this diazotizing ba containinggms. sodium nitrite and 200 cc. concentrated hydrochloric acid, and areMore-'-" vigorously moved-in same for about half an hour at 15. C. Thesucceeding developing bath consists of 20 gms. naphthylamme'chlorhydrate and 8 gms. sodium bicarbonate. The goods are treated inthe develop ing'bat-h for one hour, then washed for a short .time, andthen introduced into the second diazotizing'bath, which is of the samecomposition as the first diazotizing bath. The goods then receiveonewashing in soft water and one in hard water. Tlien follows a secondweakly alkaline developing bath, consistin of 20 litres of. water, .5litres boiled-off liquor, 30 'gms, of amino 'naphthol and 5% magnesiumchloride, all 'calculatedon the weight of the goods. The

one ofthe components to be ooupled in presence of soluble chloride andprotective colloid.

2. Process of dyeing cellulose acetates in artificial silk, film orother form, with developing dyes, comprising applying both. base anddeveloper in presence of soluble chloride and protective colloid.

In testimony whereof I have hereunto subscribed my name.

Do. RENE CLAVEL.

